Water soluble lipopolymer for gene delivery

초록

Water soluble lipopolymer (WSLP, which consisted of polyethylenimine (PEI2K, 2 kDa) and cholesterol, was synthesized and characterized as a gene carrier. Acid-base titration showed that WSLP had a proton-buffering effect. The size of WSLP/plasmid DNA (pDNA) complex was around 70 nm. WSLP has higher transfection efficiency than PEIm, SuperFect, and lipofectamine. In addition, WSLP has less cytotoxicity than high moelcular weight PEI (PEI25K, 25 kDa), SuperFect, and lipofectamine. Dexamethasone is apotent glucocorticoid with anti-inflammaotry effect. To apply anti-inflammatory effect of dexamethasone to gene therapy, dexamethasone-conjugated polyethylenimine (PEI-Dexa) was synthesized and evaluated as a dual-funcational water-soluble lipopolymer. To confirm the anti-inflammatory effect of PEI-Dexa, PEI-Dexa/pbeta-Luc complexes were transfected into LPS stimulated macrophage cell lin (RAW 264.7). After 24 hrs, ELISA was performed to measure the levels of TNF-alpha and IL-6. The results showed that PEI-Dexa transfected RAW 264.7 cells secreated less amount of inflammaotry cytokines compared to LPS induced control cells. However, PEI 2K/pbeta-Luc and PEI 25K/Pbeta-Luc complexes transfected cells did not show this effect. Then, PEI-Dexa was characterized as a gene carrier. In vitro transfection and MTT assays showed that PEI-Dexa shoed lower toxicity to L2 lung epithelial cells than PEI25K. In addition, PEI-Dexa had transfection efficiency comparable to PEI 25K.